Hi Viper, i am assuming that the basket may be the culprit as it was mentioned they are made of cheese....Yamacheese.
Anyway, it is still a good idea as i have read on other forums of guys using H model baskets on G model 125's but had to do mods to the gear. I have posted up an excerpt from VintageMX.US.. i used the cached version as a lot of people cannot open pages from his site.
http://webcache.googleusercontent.com/search?q=cache:iXjYx3xexEsJ:www.vintagemx.us/message_board/viewtopic.php%3Fsid%3D%26t%3D1017+&cd=1&hl=en&ct=clnk&gl=au PostPosted: Wed Jul 08, 2009 3:16 pm Post subject: 1980 YZ125G clutch basket suggestions Reply with quote
1980 YZ125G....Was wondering what clutch baskets people are using. I have heard that the 1981 YZ125 will work but you have to add another clutch plate. I`ve heard the later YZ100 will work but you have to use the original primary gear from the yz125. Also has anyone used the Billet Aluminum one made by Mitaka in the U.K? Has anyone actually used something other than the stock basket and knows for sure it will fit and work good. Thanks, Jason
PostPosted: Thu Jul 09, 2009 4:29 am Post subject: Reply with quote
Jason, the '81 H basket does in fact use a 6th friction plate and it bolts right on. HOWEVER, if you do not modify it, after some time the tips of the helical cut teeth on the primary gear will start to chip off. This is because the big gear on the back of the basket is thinner, and doesn't properly engage the primary. About 2mm needs to be milled off the the back of the basket where the small kickstarter gear slips in, in order for the whole clutch to move inward.
There was a guy on this site who announced he would fab some billet baskets for the G if enough people replied. I replied twice, but got no reply. I'm curious about the ones in the UK, or anywhere for that matter, as good stockers are rare, and were not very strong to begin with.
Ken
PostPosted: Thu Jul 09, 2009 4:32 pm Post subject: Reply with quote
Hey Ken, thanks for all the usefull info. I actually bought a complete 81yz125 engine today from a local guy here. The basket is good and I'm going to check into getting it milled like you said. The primary gear is thicker on the 81 compared to the 80. I wonder if it will have to come off for them to mill it? Have you ever seperated the gear from the basket. Where or who did you get the rivets from to put back in it? Thanks again, Jason
PostPosted: Thu Jul 09, 2009 4:59 pm Post subject: Reply with quote
I did not mean the primary gear in the previous post but rather the gear mounted to the basket. Sorry I'm learning.
PostPosted: Fri Jul 10, 2009 4:04 am Post subject: Reply with quote
No need to take off the gear from the basket! The area to be milled is small, and is where the pressed in small gear stops against the big gear. Call me @ 817 790-6773. I'll hunt up my notes and tell you how much to take off.
Ken
PostPosted: Sun Jul 12, 2009 12:16 pm Post subject: 1980 YZ125G clutch Reply with quote
I'm lurking in this discussion because I have the same issues. I got a 81IT175 clutch which is the same as a 81 YZ125. I can see by the wear marks on the 19T gear on the back that it was only half engaged.
Are you milling 2mm off the shoulder on the big primary gear, and 2mm off the engagement tabs on the 19T gear? How do you compensate for the axial play of the basket on the shaft?
I've got my motor put together with 1980 basket and 1981 plates, but haven't run it yet.
PostPosted: Mon Jul 13, 2009 5:07 am Post subject: Reply with quote
First; I am NOT a professional engine builder or tuner, so as far as any long-term wear problems associated with this modification, I can't guarantee anything. I've been racing my 125 for 6-8 months with no problem.
My "goal" was to get the H basket 2.5mm further back towards engine centerline in order for the primary gear to properly engage the clutch gear. The 19T kickstart gear was secondary in my thought process. I have NOT checked to see wear marks on it since this mod, but the bike kicks over fine.
I did not grind the 19T gear at all, only the big gear; 2.5mm off the high part of the shoulder, and the same off the low part. The thin brass bushing will also have to be shortened. I did that with a belt sander. Replacement of that bushing is the only way I know to reduce "axial play".
You may need to grind the 6 rivets .5mm-1mm in order to avoid them contacting the free gear that engages the 19T gear. It is close. the more worn that bushing gets, the more likely they are to rub that gear.
Hope this helps, Ken.
